1. Field of the Invention
This invention relates to heat resistant alloys useful for structures for use in the interior of heating furnaces, homogenizing furnaces and the like, such as rollers or rails on the floor of the furnace.
2. Description of the Prior Art
High-cobalt alloys containing 20 to 50% by weight of Co are known as heat resistant alloys useful for the structures, such as floor rails and rollers, to be installed in heating furnaces, homogenizing furnaces and like furnaces. These alloys have the advantage that the high Co content enables the structure to retain the desired strength at high temperatures. However, when rails and rollers are used in the furnace at a high temperature of 900.degree. to 1200.degree. C. for supporting thick steel plates and passing them through the furnace for heat treatment, the alloy is liable to react with scales formed on the steel plate, permitting the scales to thermally adhere to the surface of the rail or roller as deposit. This phenomenon, so-called "pick-up", in turn produces a flaw on the surface of the steel plate and impairs the quality of the product. Additionally, such an alloy contains a large quantity of expensive Co and is therefore costly and economically disadvantageous.